Company network using time slot reuse

ABSTRACT

An arrangement and a device comprises a mobile data and communication network within a predetermined geographical area. The device operates with first and second functions that can consist of, for example, company and/or customers functions and communication and/or slave functions respectively. Two or more units in the first function are synchronized with each other as regards time and frequency in order to act, from the point of view of connection and disconnection functions, as a common first unit for second units that carry out the second function. Time consuming handshaking procedures are then avoided for the second units when these one&#39;s are moving and shifting between part areas of said predetermined area and the total system will operate rapidly in this respect.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a U.S. national phase application filed under 35U.S.C. §371 of International Application PCT/SE01/02634, filed on Nov.29, 2001, designating the United States, which claims priority fromSwedish Application 0004617-7, filed Dec. 12, 2000, which are herebyincorporated herein by reference in their entirety.

BACKGROUND

The present invention relates among other things to a communicationsystem where the transmission of signals between different nodes takesplace via company nodes (master nodes) that allocates permission totransmit to the respective mobile customer (slave) nodes in given timeslots. The invention also relates to a device in the form of a mobiledata and telecommunications network within a predetermined geographicalarea, for example within a company, factory, hospital, etc, and workingwith first functions, for example in the form of company (master)functions and second functions, for example in the form of communicationfunctions and/or customers (slave) functions, established by means offixed and/or movable nodes and/or mobile units. In addition, theinvention relates to an arrangement with a mobile telecommunicationsand/or data network located in a geographical area, which networkcomprises company (master) functions and mobile customer (slave)functions.

A well-established way of carrying out wireless communication is toset-up a cell with a base station that has a number of transmitting andreceiving stations within its area. These communicate with each othervia the base station, that is the transmitting station has an “up” linkto the base station and the receiving station has a “down” link. Awell-known system with this construction is Bluetooth. The invention isdescribed using Bluetooth as an example, but can also be implemented inall similar systems.

Bluetooth allows a master to provide service to up to seven slaves thatare active. An unlimited number of slaves can be put in Park Mode andcan either be activated by the master or activate themselves. A mastercan have a very restricted range. It is usually a question of arestriction to approximately 10 m, but technically a considerably largerrange can be achieved. Bluetooth provides standardized profiles that canbe used in the present invention, for example, K1-6 and K9 are relevant.

It is desirable to be able to use Bluetooth standard units as headsets,PCs, mobile telephones, etc, in order to provide service from varioussources, for example companies, within their geographical area, forexample, within a department store, a petrol station, etc. A problem isthat there are many customers in the area, and that each node in thecompany's network can only handle at most seven customers at a time.This means that it is necessary to have many masters within the area,and as these utilize the frequency range independent of each other,there is an inefficient utilization of the local bandwidth. In addition,the customers, that is the Bluetooth slaves, must re-synchronize orrather execute handshakings frequently to new masters. Said handshakingprocedures are time consuming in Bluetooth.

Solution

The company arranges a Bluetooth network in the usual way and setsitself up as the master in the pico-network. By this means, full controlis obtained of the bandwidth utilization for the slaves connected to thepico-network. By synchronizing for time and frequency all the masternodes belonging to the company within the area, these can appear to beone and the same master to all the slaves within the area.

SUMMARY

Design of the Company's System

The company's nodes differ from the Bluetooth specification in that theyare synchronized to one and the same clock, that is each node in thecompany refers to one and the same Bluetooth time. In addition, theirfrequency hop is synchronized. All use the same frequency and changefrequencies simultaneously, and they use the same BD_ADDRESS. In thisway, the Bluetooth nodes belonging to the customers that are connectedup to the company network at any time, perceive that they areinteracting with one and same Bluetooth master regardless of whichcompany node is within their range.

At each node in the company system there is a gateway to a commonnetwork for the company that can be cable-based or wireless. In thewireless version, certain time slots in the planning of the nodes'Bluetooth schedule can be reserved for communication between adjacentcompany nodes. Through the common company network, the nodes canexchange messages with each other and/or a central node belonging to thecompany with database and connection to other public networks such asthe Internet, public telephone network, etc.

The company nodes are preferably permanently installed and theirgeographical location is arranged to suit their antenna layout or viceversa, so that a suitable range pattern and overlap pattern is obtainedbetween them, and the time slots are scheduled so that the availablebandwidth serves an optimal number of customer nodes in the system withregard to quality and availability. As the company nodes aresynchronized with each other, the company network occupies a minimalpart of the available bandwidth. The concept can be developed further sothat the company can have several parallel networks that are coordinatedwith each other so that collisions between them do not occur. In thisway, the maximal space is created for other Bluetooth nodes within thearea.

Synchronization

The customer nodes synchronize themselves to the company networkpreferably at special synchronization nodes, but alternatively this canbe carried out at any company node. The synchronization method does notdiffer from the Bluetooth standard. In conjunction with thesynchronization, appropriate information is exchanged for furtherservice provision in the system, for example, name, account number,customer profile, etc, and is updated in the central database. Thecentral unit can be connected to a GPS node and can thereby besynchronized to GPS time, whereby the company's Bluetooth time can besynchronized to GPS time. Customer nodes that are synchronized to GPStime and that have the ability to synchronize their Bluetooth time tothis, can thereby be synchronized to the company's nodes viasoftware/data sent to them without synchronizing themselves via thesynchronization node, or alternatively, after having synchronizedthemselves once in the conventional way, they will thereafter bepermanently synchronized via the GPS time.

Operation

As all the company nodes are able to communicate with each other andwith the central node, the active company nodes can be served in asuitable way. The different company nodes are scheduled so that theyhave particular exclusive time slots within their area of coverage.Outside the area of coverage, the same time slots can be allocated toother company nodes. In overlapping areas, a time slot that has beenallocated to a company node can be listened to by the other companynodes. By measuring the signal strength (RSSI), an adjacent node cantake over a customer node from an adjacent company node. There areseveral more or less sophisticated solutions for this. The simplest canbe to take over when the signal strength exceeds a pre-programmedthreshold value. Another can be that during a transitional stage, two(or more) company nodes allocate the customer node a time slot belongingto the respective company node. The information from the customer nodecan be used by the company node that currently requires it, as all canlisten. Sniff, Hold and Park Mode can be used according to the Bluetoothspecification in order to utilize the available bandwidth in the optimalway. Beacon signal, Beacon access windows, etc, can be synchronizedwithin the whole company, and customer nodes can thereby attractattention when the customer needs to access the company system.

Scenario

The customer drives within range of a synchronization node in thecompany system. The customer's BT node is synchronized to the companynetwork and the customer is asked what he is interested in. The customerreplies, for example, “shoes”. The company system gives a list of allthe places that sell shoes within the system and what type of shoes. Thecustomer selects one of the suggestions and the company system informshim of the nearest available parking place. The customer can be directedto this either via his own navigation system using GPS coordinates, orby the respective company nodes on the way giving appropriatedirections. Once he is parked, the nearest company node sends theinformation about the car's parking place to the central node, whichstores it in memory. The customer now leaves the car and the car's BTnode provides the requisite information to the driver and passengers' BTnodes and information about which these are to the company system. Thedriver and passenger nodes connect to the company system. Theinformation is saved in the central system. As the customers move aroundin the company system, this is updated and one company node is activewhile adjacent nodes monitor the communication and are ready to takeover the respective node. The customer nodes can be directed to go intoPark Mode by the company system when this is appropriate. The customernodes can themselves also request to be directed into Park Mode. PM_ADDRcan be used and in this way the company can wake up the nodes at regularintervals. Several customer nodes will have the same PM_ADDR, but as inmost cases they will be in contact with different company nodes, theywill not collide. With a PM_ADDR, the company system obtains informationabout where a plurality of customer nodes are to be found in the system.BD_ADDR can always be used if there is a need to wake a particularcustomer node. The company system can choose which company nodes are tosend the command. This can be one, several or all of them. If severalgive the command, this preferably takes place simultaneously. Withknowledge of the most recent customer position, suitably located companynodes can be used for the purpose.

Our family has now arrived at the shoe shop. This is the location of anumber of company nodes. These can in turn be connected, via radio,infrared or cables, to one or more shoe-shop nodes that correspondlocally to the central node. These local central nodes are connected tothe company system. The local node suitably covers a geographical areasuch that it can serve up to six or seven customers. The customer sees ashoe he is interested in and reads its identity. (In a furtherdevelopment of the concept, the information can be scanned in, enteredvia an electronic tag, etc.) He asks the system whether it is availablein size 45. The system checks whether such is the case and informs himof the result. If the shoes are available, the system asks the customerif he wants to try on a pair. If he replies in the affirmative, thesystem informs the nearest assistant (who is also connected to thecompany system) of the request and where the customer is located. Thecustomer tries on the shoes and likes them. The customer informs thesystem that he wants to buy the pair. The system informs him of theprice and which account is to be charged and asks the customer for aconfirmation. The customer gives a confirmation and the company systemimplements the transaction. If the shoes have an anti-theft device, thisis deactivated in an appropriate way. The customer takes the shoes andleaves.

Now the husband and wife have been separated for a short while. Thehusband asks the system where his wife, or more precisely where hiswife's customer node, is located. The system checks via the central nodewhere she most recently made contact. If her node is active in thesystem or has recently been active, then information is provided aboutthe location. This indication can refer to a geographical referencesystem or be in descriptive text, for example “in the hosiery departmentof the ladies outfitting shop ‘Damex’.” The company system can offerdirections to his wife, or alternatively give her a message or set up avoice link.

In a further development of the concept, all information between thecustomer and the company system can be carried out by voice. For thecustomer, it is then as though he were talking to a person whorepresents the company. In the company system, the voice processing canbe carried out at several different levels, locally in the nearestcompany node, in the local central node to which the nearest companynode is connected, or in the central node or in an even higher system,depending upon what is technically the most appropriate.

What the system can offer the company in question concerning customerinformation should be obvious and is not dealt with here.

The concept of the invention can be developed further for other areasand types of service, for example, medical care, training, factorycommunication, etc.

BRIEF DESCRIPTION OF THE DRAWINGS

An arrangement and a device that has the significant characteristics ofthe invention will be described below with reference to the attachedfigures in which

FIG. 1 shows schematically in outline form a communication systemarranged within a geographical area with units that carry out basestation functions or act as masters and mobile units that are to utilizethe network in question,

FIG. 2 shows schematically in outline form a different embodiment to theembodiment shown in FIG. 1, and

FIG. 3 shows principally and a table of the hop operation.

DETAILED DESCRIPTION

In FIG. 1 a number of company nodes are indicated by 1, 2, 3, 4 and 5.The nodes are connected to a company network 6, to which a number ofsynchronization nodes 7 are also connected. The company has a centralnode 8 with one or more databases 9. The company network can beconnected via the central node to an external network 10, which canconsist of a data and/or telecommunications network, for example thepublic data and/or telecommunications network. A clock synchronizationnode is also connected to the central node. The clock synchronizationnode can be influenced by the so-called GPS function 12 and obtain theGPS time via a wireless link 13 in a known way. The geographical area inquestion, that can consist of a company, hospital, factory, etc., hasbeen principally indicated by 14. Mobile units or customer nodes thatenter the geographical system 14 have been indicated by 15, 16, 17 inFIG. 1. The entering customer nodes in question can be synchronized bymeans of a synchronization node, cf. the mobile unit or customer node 17that is assumed to be synchronized as regards time with thesynchronization node 7 in FIG. 1. It is also possible to implement theclock synchronization function in other company node(s). The customernodes communicate with the company/synchronization nodes via wirelessconnections 18, 19, 20. The connection and disconnection functions canbe controlled by buttons and/or be voice-controlled in a known way.Thus, in accordance with the above, all exchange of information betweenthe customer and the company system can be carried out by means of voicecommunication, where it is for the customer as though he or she weretalking to a person who represents the company. The voice processing canbe carried out at several different levels in accordance with the above.

The embodiment shown in FIG. 2 conforms in the main with the embodimentdescribed in connection with FIG. 1. The difference is that FIG. 2comprises a case where a company node 21 connected to the companynetwork 6 in turn acts as a higher-level unit in relation to a number ofcompany subsidiary nodes 22, 23, 24, and 25. In this case, the saidcompany node 21 has a local database 26. In this way, the system can,for example, serve a number of subsidiary geographical areas 1′, 2′, 3′,4′ and 5′ that are located within an overall geographical area 14. Puredata communication and/or telecommunication can be carried out betweenthe units in the system, but, for example, in this embodiment of thesystem, monitoring and/or controlling data can alternatively oradditionally be exchanged both as signals and voice commands forprocesses, carrying out commands, etc.

The invention is not limited to the embodiment described above by way ofexample, but can be subject to modifications within the scope of thefollowing claims and concept of the invention.

1. A wireless communication system, comprising: a plurality of masternodes comprising wireless communication devices; at least one slave nodecomprising at least one wireless communication device; the plurality ofmaster nodes arranged to provide communication coverage for at leastsubsidiary geographic areas that are located within an overallgeographical area wherein at least some of the subsidiary geographicareas are non-adjacent to one another, at least one of the plurality ofmaster nodes configured to activate and deactivate the at least oneslave node for communication within an associated portion of the overallgeographic area; wherein all of the plurality of master nodes areconfigured to in operation operate continuously with a coordinated timeslot and a common Bluetooth frequency, wherein shifting of each of theplurality of master nodes to a different Bluetooth frequency issynchronized; wherein the plurality of master nodes are configured tocommunicate with the at least one slave node using said coordinated timeslot and said common Bluetooth frequency so as to appear to the at leastone slave node as a common master node with respect to the at least oneslave node having moved between the subsidiary geographic areas of saidpredetermined geographic area.
 2. The system of claim 1, furthercomprising a time and frequency synchronizing node configured tocoordinate time slot usage and frequency utilization.
 3. The system ofclaim 2, wherein the time and frequency synchronizing node comprises aGPS receiver.
 4. The system of claim 1, wherein the plurality of masternodes are operatively connected to a network.
 5. The system of claim 1,further comprising a database accessible by at least one of theplurality of master nodes.
 6. The system of claim 5, wherein thedatabase is accessible by said at least one of the plurality of masternodes through the network.
 7. The system of claim 1, wherein the atleast one slave node is synchronized through any of the plurality ofmaster nodes via a Bluetooth standard synchronization method.
 8. Thesystem of claim 7, wherein, responsive to synchronizing the at least oneslave node, the system is configured to exchange information, theinformation including one or more of a name, an account number, and acustomer profile that is updated in a central database.
 9. The system ofclaim 1, the system further comprising a GPS node that synchronizes aBluetooth system time to a GPS time.
 10. The system of claim 9, whereinresponsive to the at least one slave node being synchronized to GPStime, the at least one slave node is synchronized with respect to timeto the plurality of master nodes with data sent from the at least one ofthe plurality of master nodes, wherein the at least one slave node thatis synchronized to the GPS time synchronizes an associated Bluetoothtime to the GPS time so as to achieve synchronization to the pluralityof master nodes for data exchange therebetween.
 11. The system of claim1, further comprising overlapping coverage areas between two or more ofthe plurality of master nodes, wherein an adjacent master node mayassume control of the at least one slave node from the particular masternode in response to a received signal strength measured at the adjacentmaster node.
 12. The system of claim 1, wherein responsive to the atleast one slave node being synchronized to GPS time, the at least oneslave node is synchronized with respect to time to the plurality ofmaster nodes with data sent from the at least one of the plurality ofmaster nodes.
 13. The system of claim 1, wherein the plurality of masternodes are further configured to operate with a second coordinated timeslot associated with a second common frequency, wherein the plurality ofmaster nodes shift to a different second common frequency substantiallysimultaneously, and wherein the master nodes comprise a plurality ofseparate and parallel networks configured to communicate with the atleast one slave node.
 14. A system for wireless communication, thesystem comprising: first units comprising wireless communicationdevices; second units comprising wireless communication devices; thefirst units arranged to carry out base station functions withinsubsidiary geographical areas that are located within a predeterminedgeographical area wherein at least some of the subsidiary geographicareas are non-adjacent to one another; the second units arranged tocarry out communication and data functions within the predeterminedgeographic area; wherein the first units are configured to communicatewith the second units using a Bluetooth compatible protocol; wherein allof the first units are configured to in operation operate continuouslywith a coordinated time slot and a common Bluetooth frequency, whereinshifting of each of the plurality of master nodes to a differentBluetooth frequency is synchronized; and wherein the first units areconfigured to communicate with at least one of the second units usingsaid coordinated time slot and said common Bluetooth frequency so as toappear to the at least one second unit as a common base station withrespect to the at least one second unit having moved between thesubsidiary geographic areas of said predetermined geographic area. 15.The system of claim 14, wherein the first and second units operatingwithin said predetermined geographical area are synchronized to a commontime reference.
 16. The system of claim 15, wherein said common timereference corresponds to a Bluetooth time reference.
 17. The system ofclaim 14, wherein said first and second units use identical addressfunctions.
 18. The system of claim 14, further comprising a commonnetwork accessible by one or more of the first units.
 19. The system ofclaim 18, wherein the common network comprises a wireless Bluetoothnetwork, wherein Bluetooth time slot schedules for each of the first andsecond units are allocated such that selected time slots are reservedfor communication between adjacent first units.
 20. The system of claim14, wherein responsive to the second units being synchronized to GPStime, the second units are synchronized to the first units with respectto time in response to data sent from the first units.
 21. Acommunications system within a predetermined total geographic area, thesystem comprising: first units comprising wireless communicationdevices; second units comprising wireless communication devices; thefirst units each comprising a base station having base station capacitytherein that covers a portion of the total geographic area, whereindifferent overlapping portions of the total geographic area are coveredby associated first units and at least some of the portions arenon-adjacent to one another; said first units being configured to be inoperation operatively connected to an external network; said first unitsbeing configured to be in operation synchronized with each other tooperate continuously with a coordinated time slot and a common Bluetoothfrequency, wherein shifting of each of the plurality of first nodes to adifferent Bluetooth frequency is synchronized; wherein the second unitscomprise slave units which are configured to in operation be positionedin or enter into the different overlapping portions of the totalgeographic area; and wherein the first units are configured tocommunicate with at least one of the second units using said coordinatedtime slot and said common Bluetooth frequency so as to appear to the atleast one of the second units as a common master node with respect tothe at least one of the second units having moved between portions ofthe total geographic area.
 22. A system for wireless communication, thesystem comprising: first units comprising a wireless communicationdevices; the first units configured to carry out base station functionswithin overlapping geographical areas located within a predeterminedgeographical area wherein at least some of the overlapping geographicalareas are non-adjacent to one another; and wherein the first units areconfigured to: communicate using a Bluetooth compatible protocol with atleast one second unit comprising a wireless communication device withinthe predetermined geographical area; operate continuously with acoordinated time slot and a common Bluetooth frequency, wherein shiftingof each of the first nodes to a different Bluetooth frequency issynchronized; and communicate with at least one of the second unitsusing said coordinated time slot and said common Bluetooth frequency soas to appear to the at least one second unit as a common master nodewith respect to the at least one second unit having moved betweenoverlapping geographical areas.